Problema Solution
The average of a list of 6 numbers is 20. If we remove one of the numbers, the average of the remaining numbers is 15. What is the number that was removed?
Answer provided by our tutors
(p1+p2+p3+p4+p5+p6)/6=20
=>(p1+p2+p3+p4+p5+p6)=120
now
(p1+p2+p3+p4+p5)=75
so number removed is (p1+p2+p3+p4+p5+p6)-(p1+p2+p3+p4+p5)=120-75=45